(2,1*10^-1)*(4*10^-2)=0,21*0,04=0,0084>0,008
<span>(2,1*10^-1)*(4*10^-2) и 0,008</span>
<span>(21:-1)*(40: -2)= -21*-20= 420</span>
<span>420>0.008</span>
<span> </span>